April 2011, Volume 2, No.2

International Journal of Chemical and Environmental Engineering

Impact of Solid Waste Leachate on Ground Water

Sources-A Case Study Anita Agrawal*1 Rama Pandey 2, M.L. Agrawal 3 1.Reader and Head of the Dept., Chemistry Lakhmi Chand Institute of Technology, Bilspur 2.Prof. & Head, Dept of Chemistry Pt. R. S. University, Raipur 3.Principal, Lakhmi Chand Institute of Technology, Bilspur * Corresponding author: anita_mla@yahoo.co.in

AbstractIll-managed municipal solid waste particularly in developing countries like India, have lead to the serious socio-environmental

problem. Due to limited financial resources, it is given least priority to municipal solid waste management (MSWM) in India. The

current practice of uncontrolled dumping of waste on the outskirts of towns/cities has created a serious environmental and public

health problem. The municipal solid waste dump when comes in contact with the rainwater, generate leachate. It is important to know

the characteristics of this leachate for effective management of solid waste dumps as well as to evaluate the probable impacts of this

leachate on ground water sources and surrounding environment. The assessment of impacts on ground water sources near to MSW

dumps is of considerable importance in management and disposal of solid waste. The leachate may greatly affect the ground water

sources near to the dumpsites. In the present study an attempt has been made to investigate the relationship between the characteristics

of leachate generated from municipal solid waste and its impact on surrounding ground water sources.

Keywords: Municipal solid waste (MSW) dumps, Leachate characteristics, Ground water pollution.

1. Introduction Increased rate of exploitation of natural resources and

generation of municipal solid waste (MSW) is the result

of rapid population growth and urbanization in

developing countries. The solid waste disposal in open

dumps is a very common feature in developing countries.

With increased population, urbanization, and

industrialization the quantum of MSW generated

increased many fold and it is beyond the assimilation

capacity of nature. The solid waste dumps if not managed

properly, may cause many types of socio-environmental

problems [1], like ground water pollution, air pollution,

soil contamination, odour nuisance, fly nuisance etc.

Increasing awareness for health and environmental effects

of MSW dumping has the requirement for proper

assessment of harmful effects of it.

The quantum of municipal solid waste generated in

India is about 0.15 million tonnes per day. That is

approximately 50 million tonnes annually. Out of the total

municipal waste collected, on an average 94% is dumped

on land and 5% is composted. The average rate of MSW

generation (0.35 to 0.6 kg/ person/day) is very low as

compared to developed countries, but due to rapid growth

of population and increased urbanization solid waste

generated is of very large amount. In most of the cities

and towns the MSW is dumped on low-lying area without

following the guidelines for safe disposal of solid waste

[2]. Most of the municipal solid waste of Indian cities,

which is collected, is dumped on land in a more or less

uncontrolled manner. The placement and compaction of

municipal wastes in landfills facilitates the development

of facultative and anaerobic conditions that promotes

biological decomposition of land filled wastes. Such

inadequate waste disposal creates serious environmental

problems that affect health of humans and animals and

cause serious economic and other welfare losses.

As water filters through any material, chemicals in the

material may dissolve in the water, this process is called

leaching and the resulting mixture is called leachate. As

water percolates through MSW, it makes a leachate that

consists of decomposing organic matter combined with

different metals from rusting cans, discarded batteries and

appliances [3]. It may also contain paints, pesticides,

cleaning fluids, newspaper inks, and other chemicals as

well as bacteria and viruses. Leachate is produced when

the waste becomes saturated with water [4]. The leachate

generated from solid waste dumps may have the potential

to pollute the surrounding water sources and

contamination of soil also [5]. The most serious problem

is groundwater contamination [6]. The U.S.

Environmental Protection Agency (EPA) estimates that

between 0.1% and 0.4% of usable surface aquifers are

contaminated by industrial impoundments and landfills.

The adverse impact on the surrounding atmosphere due to

leachate will depend on the characteristics of this leachate

[7]. So it becomes very important to assess the

114

characteristics of the leachate generated as well as the

relationship between the characteristics of leachate and its

impact on water quality of the surrounding sources.

2. Material and Method

2.1 Study Area location

Study area was taken for MSW dumps of Raipur

town. Raipur is in Chhattisgarh state of India, with a

population of 1 million (approx.) having latitude of

21o14’ N and longitude of 81o38’ E. It is on Bombay-

Hawrah main railway route. It sprawls over a radius of 8-

10 km and experiences a mainly tropical climate with an

estimated annual rainfall of about 1250 mm. In order to

determine the characteristics of leachate generated from

MSW dumps.

Two locations of the MSW dumps were selected for

this study namely- Rawan bhata and Gudhiyari. These

MSW dumps are located on the outskirt of the city as

shown in Fig 1. These landfill sites are owned by

Municipal Corporation of Raipur. Landfill sites are not

properly managed since the operational practices at the

site do not follow the standard, normal practices but these

landfill are nothing more than random dumping of solid

waste in uncontrolled manner without any engineered

design. Both landfill cover about 4 hectares of land with

solid wastes having being deposited to an estimated

average depth of about 1.5 meters. It has been used for

municipal solid waste disposal for over 5 years. It

receives domestic, commercial and institutional wastes by

public and private users.

In the areas surrounding to these MSW dumps, three

types of water sources were found to be in use and thus

these three kinds of water sources were selected, for

taking water samples, namely- open wells (all depth less

than 20m), shallow tube wells (depth less than 20m), and

Deep tube wells (India Mark-II hand pumps) having

depth more than 50m. Deep tube wells are developed by

Government of India for providing safe drinking water to

the mass population..

2.2. Sampling and analysis

Sampling was done in the month of June-July (rainy

season) to assess the worst possible scenario. More than

10 samples were collected from each dumpsite and more

than 400 samples were collected for drinking water. Glass

bottles were used to collect leachate and groundwater

samples for chemical analyses, whereas, samples

preserved for BOD5 and COD tests were collected in

polyethylene bottles covered with aluminum foils. A few

drops of concentrated nitric acid were added to all the

water samples collected for heavy metals analysis to

preserve the samples. The samples were then transported

Rawan Bhatha

Dumping Site

Gudhiyari Dumping Site

Fig 1: Location Map of MSW Dumping Sites of Raipur City

115

in a cool box and stored under suitable temperature until

analysis

Samples of leachate as well as of water were analyzed

as per the methodologies mentioned in Standard Methods

[8]. Parameters analyzed were, a) Temperature, b) Total

Dissolved Solids (TDS) c) Total alkalinity, d) Total

hardness, e) Chloride contents, f) Dissolved Oxygen

(DO), g) Turbidity, h) pH, i) Electrical conductivity (EC),

and j) Most Probable Number (MPN), k) Heavy metals

[5, 9].

Chloride was measured by the mercuric nitrate

titrimetric method. dissolved oxygen by Winkler’s

method, alkalinity by simple titrimetric method, hardness

by EDTA titrimetric method, pH by using digital pH

meter (HACH make), turbidity by using nephelometric

turbidity meter (Toshniwal make), electrical conductivity

by using conductivity meter (HACH make) and for Most

Probable Number (MPN) Nine tubes of lactose broth

were prepared according to the size of the water sample

i.e., 0.1, 1 and 10 mL respectively for all water samples.

The test tubes were placed in incubator at 35ºC for 24 h

for gas production. BOD was determined by Winkler’s

method and COD by using HACH, COD reactor. For

determination of heavy metals (Iron, Lead, Zink, Nickel)

in leachate samples, Atomic Absorption

Spectrophotometer (Varian make) was used.

3. Result and Discussion

3.1. Leachate Characteristics:

The results of the parameters analyzed for 5 samples

from each MSW dump (Rawan Bhatha and Gudhiyari)

are shown in Table 1. The pH values for all samples are in

the limit of 6-8,temperature in the range of 24.5-26.5 0C.

TDS in case of Rawan Bhatha site is higher (4090-5860)

as compared to Gudhiyari site (2090-4069). Total

alkalinity is lower for leachate from Rawan Bhatha site

(1056-1545) as compared to Gudhiyari site (1089-1609).

Total hardness for leachate samples from Rawan Bhatha

site varies in the range (780-965) and for Gudhiyari site it

is (544-1034). Chloride content of leachate samples

shows similar trend for both the sites and varies in the

range (327-745). BOD5 of leachate from Rawan Bhatha

site are higher (6345-9430) as compared to that of

Gudhiyari site (4078-8790). COD for both sites are nearly

in the same range (8769-13760). Turbidity of leachate

samples was quite high in the range of (89-210).

Electrical Conductivity of leachate samples from Rawan

Bhatha were found higher (2038-2706) as compared to

that from Gudhiyari site (1256-2389). MPN of the

leachate samples from Rawan Bhatha site was also higher

(108-156) as compared to that of Gudhiyari site (54-83).

All four heavy metals (Iron, Lead, Zinc and Nickel) were

found in all samples of leachate from both sites in varying

concentrations. In general the leachate quality from

Rawan Bhatha MSW dump site was found to be more

polluted as compared to that of Gudhiyari site.

Table 1 Characteristics of leachate from MSW dumps of Raipur

Gudhiyari Dumping

Site

Rawan Bhatha

Dumping Site

Open well Shallow Tube well Deep Tube well

Fig 2: Location Map of Drinking Water Sampling Points Surrounding to MSW Dumps

116

3.2. Water quality of different sources:

Water quality parameters observed in the water

samples from different ground water sources (open wells,

shallow tube wells and deep tube wells) surrounding to

Rawan Bhatha MSW dump are shown in Table 2 and

similarly for ground water sources surrounding to

Gudhiyari MSW Dump are shown in Table 3. The ground

water sources are segmented as per their horizontal

distance from the dumps in 4 segments (0-10m, 11-20m,

21-50m, 51-80m). In general the values of all the

parameters are highest near to MSW dumps except the

values of DO and pH.

As the distance from MSW dumps increases the

parameter values are decreasing. The values of turbidity

and MPN are found to be critical near to MSW dumps but

after a distance of 80m it reduces.

The values of water quality parameters shown in

Table 2 and Table 3 depicts that the effect of leachate on

water quality parameters of the water sources in

surrounding of MSW dump is remarkable. The impact is

observed to be in the order of Open well > Shallow tube

well > Deep tube well.

3.3. Comparison of water quality with Indian standards of

quality:

An Indian standard for drinking water quality

given by Bureau of Indian Standards (BIS

10500:1991) is shown in Table 4. On comparing the

water quality of the ground water sources in the

surroundings of MSW dumps with the water quality

standards mentioned in Table 4, several parameters

like- alkalinity, turbidity and MPN were found to be

critical and rest of the other parameters like-

temperature, TDS, total hardness, chlorides, DO,

pH, electrical conductivity were found to be in

permissible limits. In case of open wells and shallow

tube wells, MPN is more than the permissible value

(i.e. zero) for almost every sample; it indicates the

alarming situation against water born diseases in

these areas. Water qualities of deep tube wells are

comparatively safer as compared to open wells and

shallow tube wells.

S.No. Parameter Samples from Rawan Bhatha Site

Samples from Gudhiyari Site

Sample No 1 2 3 4 5 1 2 3 4 5

1 Temperature (0C) 24.5 25 24.5 25 25.5 26.0 24.5 26.5 25.5 25.5

2 TDS (mg/L) 4400 4090 5860 5340 4210 2090 3567 2789 3245 4069

3 Total Alkalinity (mg/L) as CaCO3 1270 1056 1348 1250 1545 1345 1567 1234 1089 1609

4 Total Hardness (mg/L) as CaCO3 965 870 780 913 840 1034 770 544 679 987

5 Chlorides (mg/L) 416 567 327 657 543 456 589 745 409 653

6 BOD5 (mg/L) 8650 9430 7640 6345 9070 4078 6453 8790 7435 5674

7 COD (mg/L) 12089 13760 12655 11756 12980 8769 12456 12307 11678 9834

8 Turbidity (NTU) 200 170 90 210 160 123 132 89 107 156

9 pH 6.0 6.5 7.5 7.0 8.0 6.5 6.0 7.5 7.0 6.0

10 EC (mho/cm) 2430 2655 2038 2706 2255 1340 1256 2389 1367 1875

11 MPN/100ml 127 108 156 134 148 67 83 54 60 74

12 Heavy metals (mg/L)

(a) Iron

(b) Lead

(c) Zinc

(d) Nickel

23.7

0.30

1.20

0.10

13.2

0.20

0.95

0.09

26.7

0.45

1.60

0.06

16.4

0.15

2.30

0.90

11.2

0.25

0.85

0.15

16.3

0.25

1.30

0.07

08.6

0.10

0.90

0.15

13.7

0.15

1.25

0.09

10.6

0.15

0.85

0.10

18.8

0.20

1.05

0.08

Table 2: Qualities of different water Sources at different distances from Rawan Bhatha MSW dumps

117

3.4. Comparison of water quality with Indian standards of

quality:

An Indian standard for drinking water quality given

by Bureau of Indian Standards (BIS 10500:1991) is

shown in Table 4. On comparing the water quality of the

ground water sources in the surroundings of MSW dumps

with the water quality standards mentioned in Table 4,

several parameters like- alkalinity, turbidity and MPN

were found to be critical and rest of the other parameters

like- temperature, TDS, total hardness, chlorides, DO, pH,

electrical conductivity were found to be in permissible

limits. In case of open wells and shallow tube wells, MPN

is more than the permissible value (i.e. zero) for almost

every sample; it indicates the alarming situation against

water born diseases in these areas. Water qualities of deep

tube wells are comparatively safer as compared to open

wells and shallow tube wells.

S.No. Parameter Samples from Open Wells Samples from Shallow Tube wells

(depth < 20 m)

Samples from Deep Tube wells

(depth >50 m)

Distance of

Sampling site in m

0-10 11-20 21-50 51-80 0-10 11-20 21-50 51-80 0-10 11-20 21-50 51-80

1 Temperature (0C) 23 23 23 23 24 23 24 24 25 25 24 25

2 TDS (mg/L) 234 201 170 86 203 187 156 65 176 156 155 146

3 Total Alkalinity

(mg/L) as CaCO3

750 730 693 656 653 603 545 456 432 303 245 256

4 Total Hardness

(mg/L) as CaCO3

406 374 233 203 306 374 204 156 268 217 234 189

5 Chlorides (mg/L) 132 123 110 98 105 98 76 78 57 48 46 38

6 Dissolved Oxygen

(mg/L)

6.8 6.8 7.0 6.5 5.4 5.7 5.9 5.8 5.1 5.3 5.4 5.4

7 Turbidity (NTU) 24 17 13 9 10 9 6 1 6 5 3 1

8 pH 7.2 7.3 7.3 7.2 6.9 6.8 6.8 6.8 6.2 6.3 6.3 6.4

9 EC (mho/cm) 403 356 324 198 380 345 289 124 320 290 298 267

10 MPN/100ml 13 07 03 03 07 05 02 Nil 02 01 Nil Nil

S.No. Test Samples from Open Wells Samples from Shallow Tube

wells (depth < 20 m)

Samples from Deep Tube wells (depth

>50 m)

Distance of

Sampling site in m

0-10 11-20 21-50 51-80 0-10 11-20 21-50 51-80 0-10 11-20 21-50 51-80

1 Temperature (0C) 23 23.5 23 23.5 24 23.5 24 23 24.5 24 23.5 24

2 TDS (mg/L) 197 87 73 56 184 165 136 45 123 108 101 89

3 Total Alkalinity

(mg/L) as CaCO3

550 634 367 312 456 407 397 378 356 267 209 178

4 Total Hardness

(mg/L) as CaCO3

356 323 209 178 267 304 209 128 189 217 178 156

5 Chlorides (mg/L) 98 78 73 76 96 67 72 54 48 43 39 23

6 Dissolved Oxygen

(mg/L)

6.1 5.6 6.4 6.5 5.3 5.5 5.8 5.8 5.3 5.6 5.8 5.6

7 Turbidity (NTU) 18 13 10 7 08 9 6 3 5 5 2 Nil

8 pH 7.2 7.3 7.3 7.2 6.8 6.9 6.8 6.9 6.6 6.5 6.3 6.7

9 EC (mho/cm) 324 206 200 145 276 267 238 203 278 254 212 167

10 MPN/100ml 09 05 02 01 06 03 02 Nil 01 01 Nil Nil

Table 3: Qualities of different water Sources at different distances from Gudhiyari MSW dumps

118

Table 4: Indian standard for drinking water- Specifications (BIS

10500:1991) Sr.

No.

Parameter Desirable Limit

1. Temperature (0C) Not Mentioned

2. TDS (mg/L) 500

3. Total Alkalinity (mg/L) as

CaCO3

200

4. Total Hardness (mg/L) as

CaCO3

300

5. Chlorides (mg/L) 250

6. Dissolved Oxygen (mg/L) Not Mentioned

7. Turbidity (NTU) 5 NTU

8. pH 6.5 to 8.5

9. EC (mho/cm) Not Mentioned

10. MPN/100ml 0

11. Iron (as Fe) mg/L 0.3

12 Lead mg/L 0,05

13. Zinc mg/L 5

14. Nickel mg/L 0.05

4. Conclusions

The effect of leachate on water quality parameters of

the water sources in surrounding of MSW dump is

remarkable. The impact is observed to be in the order of

Open well > Shallow tube well > Deep tube well. Values

of water quality parameters examined for the water

samples from wells in proximity of the MSW dumping

sites are found to be higher as compared to the parameter

values of samples collected away from the dumping sites.

Heavy metals (Cu, Zn, Pb, Ni) were found in substantial

quantity in the samples of leachate from both the

locations, this may be due to the fact that town does not

have separate dumping site for hazardous waste generated

from useless mobile batteries, computer peripherals and

other electronic appliances. During percolation of

leachate through soil, its characteristics changes due to

physical, chemical and biological forces before it

contaminates the ground water hence the distance is

important. The characteristics of leachate from Rawan

Bhatha dump are found to be more critical (for all three

types of sources) as compared to the same from Gudhiyari

dumping site. The pollution of water sources in the

surrounding area of dumps are also in the agreement with

corresponding leachate characteristic. It is recommended

that no human settlement should be allowed up to a

minimum distance of 100m from MSW dumping sites.

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